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H. PiEPER, P118. ARG LAMP.

No. 423,807. Patented Mar. 18, 1890.

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(No Model.) a Sheets-Sheet-3. H. PIEPER, Fils.

ARC LAMP.

No.. 423,807. Patented Mar. 18, 1890 N. FEVER war-" m". D. C.

UNITED STATES PATENT OFFICE.

HENRI PIEPER, FILS, OF IJIEGE, BELGIUM.

ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 423,807, dated March18, 1890.

Application filed September 21, 1889. Serial No. 324,611. (No model.)Patented in Belgium March 15, 1889, No. 85,408, and in France March23,1889,No.196,916.

T0 aZZ whom it may concern:

Be it known that I, HENRI PIEPER, Fils, a subject of the King ofBelgium, residing at Liege, Kingdom of Belgium, have invented new anduseful Improvements in Electric Lamps, (for which Letters Patent havebeen granted in France, March 23, 1889, No. 196,916, and in Belgium,March 15, 1889, No. 85,408,) whereof the following is a specification.

My invention relates to electric lamps in which the light is produced bymeans of an electric circuit, a carbon rod, and two or more electrodesbeing in contact with one end surface of the said rod, so that when theelectrodes are excited the current will pass transversely through thecarbon-4v vertically to its length.

The improvements are as follows: First, one or more of the electrodes isorare arranged to be capable of moving with its point or their points ofcontact lengthwise to the carbon, and it is or they are pressed (eachseparately, if more than one is movable) against the carbon, in order tokeep the latter in certain contact with the electrodes in case it shouldnot burn away uniformly at all its points of contact; second, theelectrodes, or any of them, are made in the form of tubes open at bothends and placed at an incline, so that a current of air will passthrough them when they become heated by the carbon, the said air-currentpreventing the electrodes from being heated excessively; third, the lamphaving a movable electrode or electrodes is provided with means forswitching it out of circuit automatically, without interruption of thecurrent when the carbon is consumed, or if any portion of the sameshould break, the said means consisting in contact-surfaces on themovable electrode or electrodes and other contact-surfaces arrangedopposite thereto, and each of which is conductively connected to thepole of the lamp, being of diiferent denomination than that to which thecorresponding movable electrode is connected.

In the annexed drawings, Figure 1 is a sectional elevation of a lamphaving two electrodes and comprising my improvements. Fig. 2 is asection of the carbon rod used in the same. Fig. 3 is a sectional viewof a lamp with three electrodes, the central one being vertical andstationary, the lateral ones horizontal and movable. Fig. .L shows ineleva tion and in section the carbon rod for this lamp drawn to a largerscale. Fig. 5 is a skeleton view of a lamp with three electrodes,whereof the central one is vertical and movable, while the lateral onesare horizontal and stationary. Figs. 6 and 7 are plans of modificat-ionsof the latter, comprising, respectively, three and four horizontal andstationary electrodes. Fig. 8 represents in plan an arrangement with twocombined pairs of electrodes, which are all horizontal.

In Fig. l, A is the carbon, and B C are the two electrodes. These arepivoted at b and c to the respective posts G and II, which are fixed tothe plate D, but insulated therefrom, The post G is provided with thebindingscrew E and the post II with the bindingscrew F. The electrodesare drawn by springs r and '2" against the end of the carbon rod, whichin turn presses by gravity or, in addition thereto, by means of a weight(1, against the latter. A current introduced at E will consequently passthrough the post G and the electrode B to the carbon A, and after havingtraversed the carbon, as indicated by the arrow 1, it flows through theelectrode C and the post II to the binding-screw F, the carbon being inconsequence caused to become incandescent at its end.

In order to avoid the transmission of the current through the pivots band c, it is advantageous to connect the posts G and II with therespective electrodes B O by means of wires g 72. If with thisarrangement the carbon is consumed unequally at its points of contactwith the electrodes, so that it becomes on one side shorter than on theother, the electrode which is opposite to the point of greatestconsumption will rise at its contactmaking end, and thus remain incontact with.

the carbon, in whichsoever position the opposite electrode may be at thetime. By these means the formation of sparks and the consequent burningof the electrodes, heretofore a great inconvenience in lamps of thiskind, is completely avoided.

For the purpose of keeping the ends (I e of the electrodes cool, thesaid electrodes are perforated throughout their length, so that theyform tubes, and they are arranged to be normally somewhat inclinedupward from their point of contact. In consequence, as soon as theelectrodes become hot an air-current will arise in the perforation,which produces refrigeration.

In view of causing the lamp to be switched out of circuit automaticallyit is provided with the contact-screws t' It, carried by the respectiveinsulated brackets 2' k and the ends whereof are opposite to thecontact-points l) c of the electrodes and so adjusted that eitherelectrode on rising to a certain extent will touch the correspondingscrew. The screw 2', being above the positive electrode B, is connectedby a wire 1" with the post H, and through the same with the negativepole of the lamp, while from the other screw 71'] a wire 7c is conductedto the post G, which is in connection with the positive pole. As long asthe lamp is burning the carbon keeps the electrodes out of contact withthe screwsi and but if one of the carbon parts-for i11- stance, the partbearing on the electrode C- should break on a considerable length thespring r puts the said electrode in contact with the screw 71;, thecurrent passes from the binding-screw E through the post G, the wire70', the screw k, the electrode (3, and the post H to the screw F, thelamp being consequently switched out of circuit. If the other part ofthe carbon breaks, the wire t" and the screw '11 cause the switchingout. A like effect is brought about by either shunt, or by bothtogether, if the carbon is consumed or checked in its descent.

The carbon red A is made at the sides thicker than in the middle, asshown by Fig. 2. The said sides, which are in contact with theelectrodes when the lamp is burning, consequently present lessresistance to the current than the intermediate part, the carbon becomesuniformly incandescent upon the entire portion acted upon by thecurrent, and a light of greater power is produced than by a carbonhaving uniform resistance transversely. A like eifect may be obtained ifthe carbon rod is composed of three strips of carbons, the outer oneswhereof are more conductive than the middle one, and in this case therod may be made of equal thickness at the sides and in the middle.

The lamp represented by Fig. 3 has the sta tionary electrode L and thetwo movable electrodes G C, which are pressed against the carbon byweights a n. The electrode L is supported by and conductively connectedto the plate D by the bows (I, while the electrodes O C are pivoted tothe respective posts H and H which are screwed, by means of flanges m m,to the plate D, with interposition of insulating material, and connectedtogether by a conductive bar m To the plate D is conductively attachedthe binding-screw 1, and to the flange m the bindin -screw F, which isinsulated from the plate D. A current entering at E will consequentlypass through the plate D, the bows d, and the electrode L to the centralpart of the carbon, which rests 011 the said electrode. At this pointthe current will divide into two branches, one passing through theleft-hand portion of the carbon, the electrode C, and the post H to thebinding-screw F, while the other branch passes through the right-handportion of the carbon, the electrode C, the post 11, and the bar at tothe flange m, and ultimately also to the screw F. The carbon willconsequently be exposed to the current in a similar manner as in thefirst case, except that each half thereof is acted upon by a branch ofthe said current, the purpose thereof being to attain a betterutilization of the current, especially in lamps which are to have greatlighting-power.

Opposite to the points or contact-surfaces c c of the electrodes 0 C arearranged the screws 70 7c, screwed through the plate D, so as to be inconductive connection therewith, and opposite to the points orcontact-surfaces c and c of the said electrodes the electrode L isprovided with the arms Z Z the screws 7;. 7t} and the arms Z 7 beingadjusted at a small distance "from the respective contactsurfaces of theelectrodes .0 C,when these are in their normal position. The resultattained by this arrangement is this: If the left-hand corner of thecarbon should break, the electrode C will be brought into contact withthe screw 7: by means of the weight n. The entire current willconsequently pass from the plate D through the parts 7t (3 H m to thebinding-screw F, the lamp being thereby switched out of circuit. A likeeflect is produced by means of the electrode 0 and the screw 70 if theright-hand corner of the carbon should break. It the central part of thecarbon should from any reason become too short, the carbon will pressthe electrodes C G into contact with the arms Z Z of the electrode L,whereby the lamp is also short-circuited. \Vhen, finally, the carbon is0011- sumed, both electrodes C and C will touch against the screws 707t, and thus produce the short circuit.

As shown by Fig. 1, the carbon rod for this lamp has a thick strip inthe middle, designed to receive the current from the electrode L, and athick strip or head at each side from which the two branch currents passto the electrodes 0 G, the purpose of this form being the same as thatset forth. relatively to the form of the carbon of the lamp describedabove; but in this case, also, the lower resist ance of the portions ofthe carbon rod being in contact with the electrodes may be attained bymaking the central and the lateral strips of any kind of carbon which isin a a higher degree conductive than the carbon of which theintermediate portions are formed.

The lamp represented in a skeleton View by Fig. 5 differs substantiallyfrom the foregoing one only in this that the electrode L is made movableand pressed by a spring 0 against the central portion of the carbon rodA,while the electrodes 0 C are stationary. The means forshort-circuiting the lamp when the carbon is consumed, or if a portionthereof breaks, consist in the arms 19 p, extending from the electrodes0 and O downward and toward the electrode L, and in the arms Z 1*, fixedto the latter. The co-operation of these parts will be obvious from theforegoing description.

Although in this lamp but one of the three electrodes is movable, theconsumption of carbon is quite regular, because as soon as theconsumption begins to become less on one side the resistance opposed tothe current at this side increases and a greater portion of the currentpasses over to the other side, the consumption being thereby equalizedagain immediately.

It is evident that instead of two electrodes C 0, Figs. 3 and 4, theremay be three or more, provided the carbon rod be made with as manystrips of low resistance as there are electrodes. Thus Fig. 6 shows inplan three electrodes 0 0 0 connected together by a ring M, and a carbonrod composed of a thick central strip and three ribs with thick stripsor beads at their outer edges. Fi 7 is a plan of four electrodes 0 C 0 0connected together by a ring M, the carbon being made with four ribs. Fi8 finally shows in plan four electrodes connected in pairs to thepositive and the negative pole, the electrodes Cand 0 being united bythe annular segment M, to which is attached the positive conductor, andthe electrodes 0 C by the segment M connected with the negativeconductor. The carbon in this case forms a cross, with thick strips orbeads at the outer edges, but without such strip in the middle, there isno central electrode.

I claim as my invention- 1. In an electric lamp, the combination of acarbon rod, an electric circuit, two or more electrodes in contact withone end surface of said rod, one or more of the said electrodes beingmovable with its or their contact point or points lengthwise to the rod,and means for pressing the movable electrode or electrodes against thesurface of the same, substantially as described.

2. In an electric lamp, the combination of a carbon rod, an electriccircuit, and two or more electrodes in contact with one end of the saidrod, one or more of the said electrodes being tubular and inclinedupward from their points of contact with the carbon, substantially asspecified.

3. In an electric lamp, the combination of a carbon rod, an electriccircuit,two or more electrodes in contact with one end of the said red,one or more of the said electrodes being movable, means for pressing themovable electrode or electrodes against the carbon rod, contact surfaceson the movable electrode or electrodes, other contact-surfaces arrangedopposite thereto, and each of which is conduetively connected to thepole of the lamp, being of different denomination than that to which thecorresponding movable electrode is connected, substantially ashereinbefore set forth.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses,

HENRI PIEPER, FlLS.

Witnesses:

WM. S. PRESTON, .T. Gno'r'r.

